PURPOSE:To easily produce a high purity molten steel by generating plural arc discharges among plural electrodes, injecting non-shiftable plasma arcs from the tip parts of the electrodes, and irradiating iron ore with these arcs. CONSTITUTION:At the time of supplying each phase of three-phase output of a three-phase source 7 from current adjusting devices 4, 5, 6 to the electrodes 1, 1A, the electrodes 2, 2A and the electrodes 3, 3A, plural arcs (i.e., a multi-arc) are generated among mutual six electrodes and also the non-shiftable plasma arcs 10 are injected from the tip parts 9 of these electrodes. At the position where the plasma arc 10 irradiates, a crucible 11 charged with raw material iron ore 12 added with graphite as auxiliary reducing agent and lime, magnesium, etc., as flux, is placed. By this method, the raw material iron ore 12 is heated, fused and reduced at a ultrahigh temp. of about 4000 deg.C to produce the fused steel composition at high temp. By this method, the molten iron having good quality of low carbon, low silicon and low sulfur is directly obtd. by the reduction of the iron ore.
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